scholarly journals Interpolated spline method for a thermal distribution of a pipe with a turbulent heat flow

2021 ◽  
Vol 11 (5) ◽  
pp. 353-362
Author(s):  
Hazim Albedran ◽  
Ali Habeeb Askar ◽  
Károly Jármai ◽  
Endre Kovács
Keyword(s):  
Experimental Data ◽  
Optimization Algorithm ◽  
Linear Interpolation ◽  
Cubic Spline ◽  
Turbulent Heat ◽  
Spline Method ◽  
Thermal Distribution ◽  
Spline Curves ◽  
Curve Method ◽  
Cubic Spline Curve

This work presents an interpolated spline method to mathematically represent experimental data of a thermal distribution on a tube with heat flux. Linear regression was compared with the double linear interpolation process with an optimization algorithm and cubic spline curve method with the proposed problem. The results show that the interpolated experimental data can highly improve the efficiency of the cubic spline curves and lead to a smooth empirical equation for the experiments. The optimization algorithm chooses the interpolated points in a way that provides more minor errors.

scholarly journals A new method to predict temperature distribution on a tube at constant heat flux

2021 ◽  
Vol 11 (5) ◽  
pp. 363-372
Author(s):  
Ali Habeeb Askar ◽  
Hazim Albedran ◽  
Endre Kovács ◽  
Károly Jármai
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Temperature Distribution ◽  
Surface Temperature ◽  
Optimization Algorithm ◽  
Linear Interpolation ◽  
Electric Heater ◽  
Spline Curve ◽  
Surface Temperature Distribution ◽  
Cubic Spline Curve

Surface temperature distribution on a tube is one of the main factors affecting the calculation of the heat transfer coefficient calculation. When an electric heater heats the tube, a magnetic flux is generated that affects the thermocouples readings; therefore, an efficient fitting technique is needed to represent these readings. This work proposes an interpolated spline method to mathematically represent experimental data of a thermal distribution on a tube with heat flux. Linear regression was compared with a double linear interpolation process with an optimization algorithm and cubic spline curve method on the proposed problem. The results show that the interpolated experimental data can highly improve the regression of the spline curve. Consequently, an interpolated spline curve gives better surface temperature distribution and better estimation for the average temperature. The interpolated points on spline segments are chosen by an optimization algorithm, which is particle swarm optimization, in a way that provides more minor errors.

scholarly journals Long-Term Visit-to-Visit Mean Arterial Pressure Variability and the Risk of Heart Failure and All-Cause Mortality

2021 ◽  
Vol 8 ◽  
Author(s):  
Menghui Liu ◽  
Xiaohong Chen ◽  
Shaozhao Zhang ◽  
Yifen Lin ◽  
Zhenyu Xiong ◽  
...  
Keyword(s):  
Heart Failure ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Cox Regression ◽  
Cubic Spline ◽  
Atherosclerosis Risk In Communities ◽  
Spline Curves ◽  
Increased Risk ◽  
All Cause Mortality ◽  
Cubic Spline Curve

Background: Systolic or diastolic blood pressure (BP) variability is associated with an increased risk of cardiovascular events. We assessed whether BP variability measured by mean arterial pressure (MAP) was associated with increased risk of heart failure (HF) and death in individuals with or without hypertension.Methods: We evaluated 9,305 Atherosclerosis Risk in Communities (ARIC) study participants with or without hypertension and calculated BP variability based on MAP values from visit 1 to 4 [expressed as standard deviation (SD), average real variability (ARV), coefficient of variation (CV), and variability independent of the mean (VIM)]. Multivariate-adjusted Cox regression model and restricted cubic spline curve were used to evaluate the associations of MAP variability with all-cause mortality and HF.Results: During a median follow-up of 16.8 years, 1,511 had an HF event and 2,903 died. Individuals in the highest quartile of VIM were both associated with a 21% higher risk of all-cause mortality [hazard ratio (HR), 1.21; 95% CI, 1.09–1.35] and HF (HR, 1.21; 95% CI, 1.04–1.39) compared with the lowest quartile of VIM. Cubic spline curves reveal that the risk of deaths and HF increased with MAP variability when it reached a higher level. Results were similar in individuals with normotension (all-cause mortality: HR, 1.30; 95% CI, 1.09–1.55; HF, HR, 1.49; 95% CI, 1.12–1.98).Conclusions: In individuals with or without hypertension, greater visit-to-visit MAP variability was associated with a higher risk of all-cause mortality and HF, indicating that the BP variability assessed by MAP might be a potential risk factor for HF and death.

ACCURACY OF RIVER GEOMETRY INTERPOLATION USING CUBIC SPLINE CURVE AT ALB MISSING AREA AND INFULUENCE OF FLOW REGIME

2018 ◽  
Vol 74 (4) ◽  
pp. I_859-I_864
Author(s):  
Takayuki OKABE ◽  
Takanori YAMAZAKI ◽  
Atsumasa OZAWA ◽  
Shinichi MORITA ◽  
Shigeo HORIUCHI ◽  
...  
Keyword(s):  
Flow Regime ◽  
Cubic Spline ◽  
Spline Curve ◽  
Cubic Spline Curve

Deteriorated turbulent heat transfer (DTHT) of gas up-flow in a circular tube: Experimental data

2008 ◽  
Vol 51 (13-14) ◽  
pp. 3259-3266 ◽  
Author(s):  
J.I. Lee ◽  
P. Hejzlar ◽  
P. Saha ◽  
P. Stahle ◽  
M.S. Kazimi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Circular Tube ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat

Using Exponential Cubic Splines to Predict Low Temperature Behavior of Elastomeric Materials

1994 ◽  
Author(s):  
Terry E. Shoup ◽  
George R. Fegan
Keyword(s):  
Experimental Data ◽  
Elastic Modulus ◽  
Low Temperatures ◽  
Analytical Techniques ◽  
High Sensitivity ◽  
Considerable Difficulty ◽  
Spline Curves ◽  
Different Types ◽  
Elastomeric Materials ◽  
Energy Absorbing

Abstract Because of their desirable elastic and energy absorbing properties, elastomeric materials have been widely used as shock mounts and pressure seals. The high sensitivity of the elastic modulus of these materials to changes in temperature has been a source of considerable difficulty to the development of robust design methods based on analytical techniques. This paper presents a simple analytical method for predicting the elastic modulus for a group of five different types of elastomers when used at low temperatures. The method is based on the application of exponential cubic spline curves to smooth experimental data. The method is applied to experimental data from the literature to illustrate its usefulness.

Daytime napping is associated with retinal microcirculation: a large population-based study in China

SLEEP ◽  
2021 ◽  
Author(s):  
Xin Liu ◽  
Guowei Wang ◽  
Xiaoyan Wang ◽  
Yueye Wang ◽  
Yan Min ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Large Population ◽  
Vascular Diseases ◽  
Population Based ◽  
Cross Sectional Study ◽  
Cubic Spline ◽  
Fundus Photography ◽  
Cross Sectional ◽  
Retinal Microcirculation ◽  
Cubic Spline Curve

Abstract Study Objectives To investigate the association between daytime napping and retinal microcirculation. Methods This is a cross-sectional study from a prospective population-based cohort. 2,662 participants were recruited after quota sampling. Information on napping was collected through face-to-face interviews. Retinal vascular calibers (RVCs), including central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE), and arterio-to-venous ratio (AVR), were obtained from fundus photography. Multivariate regression and restricted cubic spline curve were performed to determine the association between RVCs and daytime napping duration. Results 56.4% participants reported daytime napping regularly. Compared to no nap, daytime nap was related to higher CRAE, with nap duration of 0.5–1 h showing the most significant association. 0.5–1 h daytime nappers displayed an average of 4.18 µm (95% confidence interval [CI] 2.45–5.91, p < 0.001) wider CRAE than non-nappers after adjustment. No significant association was found between CRVE and daytime napping. Moreover, individuals with 0.5–1 h daytime napping had a lower risk for AVR reduction (odds ratio [OR] 0.70, 95% confidence interval [CI] 0.56–0.86, p = 0.001) than non-nappers. Similar association persisted in non-hypertensive population. Restricted cubic spline indicated a J-shaped relationship between AVR reduction and nap duration. Conclusion Retinal microcirculation was positively associated with self-reported 0.5–1 h daytime napping. Better indicators of retinal microcirculation were probably related to nap duration in a J-shaped manner. Also, the possibly beneficial role of 0.5–1 h daytime napping on retinal microcirculation might be independent of clinically diagnosed vascular diseases.

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